You "can" post pics straight from your computer, by using the icon of either the "paperclip" or the "postcard" (pic of mountain/sun/yellow sky) ... that show up above this message window.
You just need to be sure that the pictures don't exceed the maximum allowed pixel count. If your pics are in the range of 640x480 pixels, they're fine. That's why most people use Photobucket, or other hosting site ... because they can upload their pics & resize them to 640x480 at the same time ... and not have to go thru the hassle of resizing them manually.
Not sure why your uploads failed ... but, it could be a weak computer, heavy traffic on your provider network, heavy traffic on Photobucket, using dial-up connection, or a host of other scenarios.
... cp